Carburetor



Nov. 2, 1954 M. l.. MENNEssoN CARBURETOR original Filed Feb. 27. 194e o S RSMY mm yu N R .tu 0 JE n W/ A United States PatentOtlice 2,693,349 Patented Nov. 2, 1954 CARBURETOR Marcel Louis Mennessoii, Neuilly-sur-Seine, France, as-

signor to Societe Solex, a society of France z claims. (ci. Zai-41) The present application, which is a division of my U. S. Patent No. 2,533,602, issued December l2, 1950, relates to carburetor devices including a main carburetor and an auxiliary carburetor to be used for starting the engine from cold and warming it up until it can be run with the main carburetor, this auxiliary carburetor being put out of action, i. e. Wholly cut off from the engine induction pipe, when the main carburetor is in normal operation.

My invention is limited to the case where the main carburetor is of the balanced type, i. e. has its constant level fuel supply chamber vented to the air intake of the induction pipe, instead of being vented directly to the atmosphere. t

Now, auxiliary starting carburetors, such as made up to the present time, include a well connected directly with the atmosphere, for instance as shown at 9 in my U. S. Patent No. 1,883,809. Such an arrangement is quite satisfactory when the constant level fuel supply chamber is vented directly to the atmosphere. But in the case of a main carburetor of the balanced type, it was found that, in normal operation, i. e. when the auxiliary starting carburetor is out of action, the presence of this auxiliary carburetor has detrimental effect on the Working of the main carburetor. In particular it may happen that the fuel in the well of the auxiliary carburetor is Wholly sucked in into the constant level chamber, after which air enters through this well into the liquid in said constant level chamber which interferes with the proper working of the main carburetor.

The object of my invention is to obviate this drawback.

For this purpose, according to my invention, the well of the auxiliary carburetor has its air inlet exclustively connected in a direct and permanent way to the fuel supply chamber above the liquid level therein.

A preferred embodiment of my invention will be hereinafter described with reference to the accompanying drawing in which the only figure shows, in diagrammatic axial section, a carburetor device made according to my invention.

The main carburetor is a balanced carburetor of any suitable construction. The figure shows by way of example, only some essential elements of a downdraught type carburetor, i. e. a body 1, an air intake 2 (generally provided with a filter), a Venturi 3 forming a mixing chamber, a nozle 4 opening into said mixing chamber, a throttle valve or butterfly valve 5, and a constant level fuel supply chamber 6 with its float 7 for feeding fuel through main jet 27 and conduit 26 to said nozzle 4.

This main carburetor is of the balanced type because the top of chamber 6 is vented exclusively to air intake 2.

The auxiliary carburetor includes a well 9 provided, at its lower part, with a calibrated orice 10 opening into the coinstant level chamber 6 below the fuel level therein. A conduit 11 starting from a point of well 9 located at a distance below the fuellevel leads, through a channel 12, to a distributing device including a mixing chamber 13 and a valve plate or disc 14 rotatable by means of a spindle 15 and an external control member 16. This plate 14 is applied on its seat, constituted for instance by a plane surface of the body 1 of the carburetor, by a spring 17 so as to be able to form a iiuidtight partition between channel 12 and chamber 13.

When plate 14 is in the open position, shown by the drawing, for bringing the auxiliary carburetor into action, i. e. when orifice 18 in plate 14 is in registry with the opening of channel 12, another orice 19 provided in plate 14 comes yopposite a passage 20 opening into the intake pipe ofthe engine, on the downstream side of throttle valve 5. Chamber 13 is permanently connected, througha calibrated orifice 22 and a conduit 21, with the air intake `2V of the main carburetor at 23. Under these conditions the depression from the engine is transmitted to chamber 13 through passage 20 and sucks in, on the one hand the air supplied through conduit 21 and calibrated orifice 22 and, on the other hand, the fuel mixture delivered through channel 12 and conduit 11 from well 9.

According to an essential feature of my invention, the upper part of well 9 communicates, at 24, directly and permanently with the constant level chamber 6 above the normal level of the fuel contained in this chamber. Thus, the free surfaces of the liquid, iii well 9 and in fuel supply chamber 6, are always exactly at the same pressure, so that, when the auxiliary carburetor is out of action (disc 14 in the closed position), the liquid level in well 9 remains the same as in chamber 6 and air cannot pass through said well and its bottom calibrated oritice 10 into the liquid in chamber 6.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eilicient embodiments of the present invention, it should be well understood that I donot wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of my invention as comprehended within the scope of the accompanying claims.

What I claim is:

l. In combination with a main carburetor including an induction pipe forming, at one end thereof, an air intake chamber, and, downstream of said air intake chamber, a mixing chamber, a throttle valve in said pipe downstream of said mixing chamber, a constant level fuel supply chamber vented to said air intake chamber and fuel conduit means, including a main jet, connecting the lower portion of said fuel supply chamber with said mixing chamber, an auxiliary starting carburetor which comprises a well in communication with the lower part of said fuel supply chamber, said well being provided with a single air inlet, this last mentioned air inlet being exclusively connected in a direct and permanent way to the portion of said fuel supply chamber above the fuel level therein, a circuit, including an auxiliary jet, wholly distinct from said fuel conduit means of the main carburetor, for connecting a point of said well below the liquid level in said fuel supply chamber with said induction pipe on the downstream side of said throttle valve, control means wholly distinct from said throttle valvefor opening or closing said circuit to place said auxiliary carburetor into or out of action, and means for connecting a point in said circuit to a point of atmospheric pressure, said control means including means operable when the auxiliary carburetor is put out of action for shutting off communication through said circuit between said Well and said point of atmospheric pressure.

2. In combination with a main carburetor including an induction pipe forming, at one end thereof, an air intake chamber, and, downstream of said air intake charnber, a mixing chamber, a throttle valve in said pipe downstream of said mixing chamber, a constant level fuel supply chamber vented to said air intake chamber and fuel conduit means, including a main jet, connecting'the lower portion of said fuel supply chamber with said mixing chamber, an auxiliaryv starting carburetor which coinprises a well having its bottom in communication with the lower part of said fuel supply chamber, the top end of said Well opening directly and permanently into the portion of said fuel supply chamber above the fuel level therein, a circuit, including an auxiliary Jet, wholly distinct from said fuel conduit means of the main carburetor, for connecting a point of said well below the liquid level in said fuel supply chamber with said induction pipe on the downstream side of said throttle valve, control means wholly distinct from said throttle valve for opening or closing said circuit to place said auxiliary carburetor into or out of action, and means for connecting a point in said circuit to a point of atmospheric pressure, said control means including means operable when the auxiliary carburetor is put out of action for shutting Number oli communication through said circuit between said Y 1,883,809 well and said point of atmospheric pressure. 2,134,877 2,419,956

References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date 41,898 1,166,734 Anderson Jan. 4, 1916 800,899

Name Date Mennesson Oct. 18, 1932 Jedrzykowski Nov. 1, 1938 Kuzelka May 6, 1947 FOREIGN PATENTS Country Date France Jan. 26, 1933 France May 11, 1936 

